/* InsightForge Air Quality — modern clean theme */

:root {
  --bg: #f3f5f7;
  --surface: #ffffff;
  --surface-alt: #f8fafc;
  --ink: #1e293b;
  --muted: #64748b;
  --accent: #0f766e;
  --accent-light: #14b8a6;
  --radius: 1rem;
  --shadow: 0 12px 28px rgba(15, 23, 42, 0.08);
  --font: "Inter", "Segoe UI", system-ui, sans-serif;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  background: var(--bg);
  font-family: var(--font);
  color: var(--ink);
  line-height: 1.6;
}

/* HEADER */
header {
  background: var(--surface);
  border-bottom: 1px solid rgba(15, 23, 42, 0.05);
  box-shadow: 0 2px 8px rgba(15, 23, 42, 0.05);
  position: sticky;
  top: 0;
  z-index: 20;
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  font-weight: 700;
  font-size: 1.2rem;
  letter-spacing: -0.01em;
  color: var(--accent);
}

nav a {
  text-decoration: none;
  color: var(--ink);
  margin-left: 1rem;
  font-weight: 500;
  transition: color 0.2s ease;
}

nav a:hover {
  color: var(--accent);
}

/* MAIN LAYOUT */
main.container {
  max-width: 1100px;
  margin: 2rem auto 4rem;
  padding: 0 1.25rem;
}

/* CARDS */
.card {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 1.5rem 2rem;
  margin-bottom: 1.5rem;
  box-shadow: var(--shadow);
  border: 1px solid rgba(15, 23, 42, 0.03);
  transition: transform 0.15s ease;
}

.card:hover {
  transform: translateY(-2px);
}

h1 {
  font-size: clamp(1.9rem, 3vw, 2.4rem);
  margin-bottom: 0.75rem;
  color: var(--ink);
}

h2 {
  font-size: 1.2rem;
  color: var(--accent);
  margin-bottom: 0.6rem;
}

p {
  margin-bottom: 0.75rem;
  color: var(--ink);
}

a {
  color: var(--accent-light);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* BREADCRUMBS */
.breadcrumbs {
  margin-bottom: 1rem;
  font-size: 0.875rem;
  color: var(--muted);
}

.breadcrumbs a {
  color: var(--muted);
}

.breadcrumbs a:hover {
  color: var(--accent);
}

/* TABLES */
table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 1rem;
  font-size: 0.95rem;
  background: var(--surface-alt);
  border-radius: 0.5rem;
  overflow: hidden;
}

th, td {
  border-bottom: 1px solid #e2e8f0;
  padding: 0.6rem 0.75rem;
  text-align: left;
}

th {
  background: var(--accent);
  color: #ffffff;
  text-transform: uppercase;
  font-size: 0.8rem;
  letter-spacing: 0.03em;
}

tr:nth-child(even) {
  background: #f9fafb;
}

tr:hover {
  background: rgba(20, 184, 166, 0.05);
}

/* FOOTER */
.footer {
  text-align: center;
  padding: 2rem 0 3rem;
  font-size: 0.8rem;
  color: var(--muted);
}

/* RESPONSIVE */
@media (max-width: 640px) {
  .header-inner {
    flex-direction: column;
    gap: 0.5rem;
  }
  nav a {
    margin-left: 0.5rem;
    font-size: 0.9rem;
  }
  .card {
    padding: 1.25rem;
  }
  h1 {
    font-size: 1.7rem;
  }
}